Lab on a Chip Blog

Dr. Joo H. Kang is currently an Assistant Professor of the Department of Biomedical Engineering, School of Life Sciences at Ulsan National Institute of Science and Technology (UNIST), Korea. He received double Bachelor’s degrees in Chemical Engineering and Life Science from Sogang University in 2002 and his M.S. and Ph.D. in Bioengineering from Korea Advanced Institute of Science and Technology (KAIST) in 2004 and 2008, respectively. He joined Children’s Hospital Boston, Harvard Medical School as a research fellow in 2009, and he continued his work at the Wyss Institute, Harvard University as a Wyss Technology Development Fellow from 2012-2016. He received several awards in his early career, including Postdoctoral Award for Professional Development from Harvard University, Wyss Technology Development Fellowship from Harvard University, Baxter Young Investigator Award from Baxter Inc., and Young Frontiers in Bio and Braining Engineering from KAIST. His research interests include multiscale biofluidic approaches for tackling infectious diseases and cancer, and miniaturized organ-mimicking microsystems.

Read Joo H. Kang’s Emerging Investigator article “Measurement of the magnetic susceptibility of subtle paramagnetic solutions using the diamagnetic repulsion of polymer microparticles” and find out more about him in the interview below:

Your recent Emerging Investigator Series paper focuses on measuring magnetic susceptibility of subtle paramagnetic solution using diamagnetic repulsion of polymer microparticles. How has your research evolved from your first article to this most recent article?

One of the research topics that interested me was to discriminate the subtle differences in the magnetic susceptibility of materials in a microfluidic regime. The first paper I published in regards to this (Kang,JH, et al., JACS, 2009) demonstrated the capability of discriminating the magnetic susceptibility of “solid microparticles” where they are diamagnetically forced to be located at a quasi-isomagnetic position in a microfluidic channel (a position where the differences of the magnetic susceptibility between the solid particles and surrounding media become nearly zero). When I was invited to make contribution to the Emerging Investigator Series of Lab on a Chip last year, I wanted to revisit this, and this time I aimed to assess the subtle magnetic susceptibility of “surrounding paramagnetic solutions”.

What aspect of your work are you most excited about at the moment?

As for the paper, I was surprised of the sensitivity of the device that can discriminate the magnetic susceptibility. We compared our results with those assessed by a conventional superconducting quantum interference device (SQUID), and found that our approach is even more sensitive than the conventional one. Likewise, we can unveil various scientific approaches when exploring fluidic regimes at the micro and nanoscale, and this is the most exciting aspect as being a part of the research community in this field.

In your opinion, what applications can your current approach be used for?

Because this is a platform technology, various applications are possible where we need to measure the magnetic susceptibility of paramagnetic solutions. Assessment of residual magnetic nanoparticles in biological samples, for examples, would be one of the potential uses. We could also use this platform to evaluate metal contamination of drinking water, such as chromium or iron oxide, which alters the magnetic susceptibility of water.

What do you find most challenging about your research?

Taking research from the “bench to products”. Since I started my independent research career, I realized that I have to make considerable efforts to get this happen while playing multiple roles at the same time. But I am enjoying it.

In which upcoming conferences or events may our readers meet you?

I am planning to attend microTAS 2019 that will be held in Basel, Switzerland this year.

How do you spend your spare time?

I am spending my time with my family, hiking, swimming, and playing soccer or games with my little son and daughter.

Which profession would you choose if you were not a scientist?

Probably an architect. This was one of the paths I was thinking of when I was a high school student.

Can you share one piece of career-related advice or wisdom with other early career scientists?

A clear vision on your own research and collaborators who you can share your vision with.

Dr. He is a tenure-track assistant professor at the University of Kansas. She received her PhD degree from the University of Alberta with professor Jed Harrison, and postdoctoral training from the University of California, Berkeley with professor Amy Herr. She is the vice chair of the ASABE Biosensor program and the Councilor of the American Electrophoresis Society. Dr. He is also the founder of Clara Biotech Inc. and the founder committee for the MidWest 3D technology society. Dr. He Received NIH Maximizing Investgator’s Research Award for Early Stage Investigators in 2019. She also received the Lab on Chip Outstanding Reviewer for the year of 2018. One of her publications also received the 2018 SLAS Technology Readers Choice Award. Her research interests include biomedical microfluidic devices and sensing approaches, 3D biomaterials, and nanodelivery, employed in programming and monitoring biomimetic immunity associated with extracellular vesicles.

Read Mei He’s Emerging Investigator article “3D-printing enabled micro-assembly of a microfluidic electroporation system for 3D tissue engineering” and find out more about her in the interview below:

Your recent Emerging Investigator Series paper focuses on “3D-printing Enabled Micro-assembly of Microfluidic Electroporation System for 3D Tissue Engineering”. How has your research evolved from your first article to this most recent article?

My first article observed the microscale evolution of porous polymer materials in the microfluidic channel when I was a PhD student. I found very interesting phenomena in the microfluidic device which actually inspired me to explore more surrounding dimensions, surface chemistry, and scales. Till to my recent article focusing on 3D geometric influence on cellular behavior and their extracellular vesicles secretion dynamics, the 3D dimension in microscale is intriguing in the biological system.

What aspect of your work are you most excited about at the moment?

I am very excited to take the microfluidic technology and phenomena into the biology world, as it will bring new investigation and discovery. Biology is still in its infancy stage, I am very excited to see how microfluidic technology could advance this growth.

In your opinion, what is the biggest impact your microfluidic electroporation system will have in tissue engineering?

Intracellular delivery of regulatory or therapeutic targets into the cell is very crucial in the field of tissue engineering and regenerative medicine. Current existing electro-transfection systems, including microfluidic platforms and commercial benchtop systems, are only able to study monolayer cell suspensions in vitro, which is incapable of clinical translation within in vivo tissue microenvironment. So developing a 3D, in vivo like tissue microenvironment with effective electro-transfection is very important to move to the clinical study in the future. We actually are more interested in downstream, precise control and manipulation of cellular machinery for secreting exosomes and extracellular vesicles under the transfection-induced stimulus, such technology is not existing yet but very important for understanding the interconnection of cargo internalization with cellular level responses elicited by exosomes delivery pathway.

What do you find most challenging about your research?

Building up an in vivo like tissue system with precise control is not straightforward. The environment in a controlled lab setting is totally different than in an in vivo biological system. So the analyzed information actually is not representative of the real situation in the human in vivo system. There are huge heterogeneities present in the cell population as well as human individuals, which poses the challenges for correctly understanding cellular system regulation, such as immunity, in our human body. Mimicking in vivo living system is very challenging, but crucial for understanding quite a few of mechanism and disease pathogenesis. Our research introduces new microfluidic technology and material solutions to solve such challenges.

In which upcoming conferences or events may our readers meet you?

I will attend next year Gorden Research Conference in Bioanalytical Sensors as well as the MicroTAS annual meeting.

How do you spend your spare time?

I have a 7-year-old boy and expecting a new baby girl this year. My spare time definitely is occupied by kids and watching them growing.

Which profession would you choose if you were not a scientist?

I always like to discover new things since I was a child. If I am not a scientist, I would like to be a greeting card designer or paleontologist.

Can you share one piece of career-related advice or wisdom with other early career scientists?

Being a life-long learner and always keeping strong scientific curiosity will definitely help with your research development. Get good mentors around you and you will appreciate their advice.

Mathieu Odijk is an associate Professor at the University of Twente running his own research theme on Micro- and Nanodevices for Chemical Analysis. He received his PhD in Electrical Engineering from the University of Twente under the guidance of Albert van den Berg for his work on electrochemical microreactors for drug screening and proteomics applications in 2011. He has broaden his scope by various research visits at EPFL Lausanne (2012), the Wyss Institute at Harvard (2013), and MIT (2014).

The common aim of his research is to design novel devices to measure chemical quantities, pushing boundaries in applications to explore unknown territory. Often, this relates to faster, or better spatially resolved measurements at lower concentrations in small volumes. Micro- and nanofabrication techniques are used to enhance electrochemical, optical or mass spectrometric readout. The ultimate goal is to create new, yet robust tools for routine use in the lab or point-of-care applications.

Read Mathieu Odijk ’s Emerging Investigator article “A miniaturized push–pull-perfusion probe for few-second sampling of neurotransmitters in the mouse brain” and find out more about him in the interview below:

How has your research evolved from your first article to your most recent Emerging Investigator article?

I have nice memories about my first paper, as it was also submitted to Lab on Chip and immediately accepted without revisions (only one small question from 1 of the referee’s). The topic of that first paper was about the design of an electrochemical microreactor to study oxidative conversions in drug metabolism studies. We have been quite successful with that topic, now extending it also in the direction of studying electrochemical oxidative protein cleavage, and disulphide bond reduction using e.g. spectroelectrochemical means.

Many “ingredients” included in that first paper also are present in current projects such as microfluidics, advanced cleanroom fabrication, and analytical chemistry. These ingredients also form a key component of the focus area of my own research group (Micro- and nanodevices for Chemical Analysis).

 What aspect of your work are you most excited about at the moment?

It is my aim to push the boundaries of existing analytical tools with respect to limit detection, spatial or temporal resolution, or enhancing the number of repeats using high-throughput technology. I’m really excited about this latest paper demonstrating a miniaturized push-pull perfusion probe, as it is indeed improving both the spatial and temporal resolution by at least 1 order of magnitude compared to commercially available probes. As such, it is a nice showcase of what can be achieved by microfluidics.

In your opinion, what are the most important questions to be asked/answered in this field of research? 

I think it is really important to focus on the final application, and find good collaboration partners. If I take this push-pull perfusion probe as example, this research originated from discussions with neuroscientist who complained about a lack of temporal information from their existing microdialysis probes. However, quite a number of papers that describe probes with microfluidic channels only demonstrate in-vitro results. As we also found out in our project, bridging the gap towards in-vivo is certainly not trivial. It requires compromises in the technological area which you would not address if you stick to in-vitro experiments.

More generally I believe that the field has matured; lab on chip technology has become a means to achieve a higher goal. In this case this higher goal is to study neurochemical processes in the brain in more detail. However, I think this project also clearly demonstrates that there can be a lot of science in engineering. In this case we had to overcome challenges in microfabrication, fluid dynamics, mass-transport, protein chemistry, and adsorption kinetics.

What do you find most challenging about your research?

What I find really interesting is that my research is very multi-disciplinary in nature, crossing traditional boundaries such as “chemistry”, “physics”, or “biology”. However, that also poses a challenge as it is easy to develop a blind spot if you are exploring a new field of research. Again I would like to stress the importance of a good collaboration with experts in these fields to prevent failures at an early stage.

In which upcoming conferences or events may our readers meet you?

That is easy: I always try to attend MicroTAS.

How do you spend your spare time?

I’m a father of two small children, aged 1 and 4. If they leave me some spare time (and energy), I like to do woodworking, cycling, and indoor climbing. I also really like outdoors ice skating, but global warming is unfortunately interfering with the number of days ice skating is possible in the Netherlands.

Which profession would you choose if you were not a scientist?

I always wanted to be an inventor, with teacher as a close runner-up. I guess becoming a scientist is actually pretty close to that childhood dream. Any alternative profession should allow me to be able to either create new things, or educate other people (or both).

Can you share one piece of career-related advice or wisdom with other early career scientists?

At various points in my tenure track, I felt pressure to perform. This can be stressful and is most definitely counter-productive. Try to keep seeing/finding the fun in science, e.g. by asking your PhD students to share their Eureka moments in the lab with you. All the rest is of lesser importance.

Dr. Han Wei Hou is currently an Assistant Professor at the School of Mechanical and Aerospace Engineering and the Lee Kong Chian School of Medicine (LKCMedicine), Nanyang Technological University (NTU), Singapore. He received his BEng (First Class Hons) and PhD degree in Biomedical Engineering from the National University of Singapore in 2008 and 2012, respectively. Upon graduation, he did his postdoctoral training at Massachusetts Institute of Technology (MIT), and subsequently joined LKCMedicine at NTU as the inaugural LKCMedicine Postdoctoral Fellow in 2014.

Dr. Hou has over 30 peer-reviewed scientific publications, and his work has been featured in online science (ScienceDaily, TheScientist, Cancerforall and Genomeweb), healthcare (News Medical), as well as technology magazines (Gizmag, Nanowerk). He has received several scientific awards including the Singapore-MIT Alliance for Research and Technology (SMART) Graduate Fellowship (2009), Young Investigator Award at the 6th World Congress of Biomechanics (2010), and LKCMedicine Postdoctoral Fellowship (2014).

His current research focus on developing novel microfluidics point-of-care testing, and biomimetic organ-on-chip technologies for translational diabetes and cardiovascular diseases research. (Research group website: www.hwhoulab.com)

Read Han Wei Hou’s Emerging Investigator article “Integrated inertial-impedance cytometry for rapid label-free leukocyte isolation and profiling of neutrophil extracellular traps (NETs)” and find out more about him in the interview below:

Your recent Emerging Investigator Series paper focuses on Integrated inertial-impedance cytometry for rapid label-free leukocyte isolation and profiling of neutrophil extracellular traps (NETs). How has your research evolved from your first article to your most recent Emerging Investigator article?

My first article when I was an undergraduate student was on the study of cancer biomechanics using microfluidics. Since then, I worked on other blood-related diseases such as malaria, sepsis and diabetes, and gradually became more interested towards microfluidics-enabled studies of host inflammation and immune responses in metabolic diseases. Regardless of disease type, our key idea is to develop integrated label-free cell sorting and biosensing approaches so that it can be cheap, fast and readily translated to clinical use. In my opinion, this work is a nice combination of all aspects.

What aspect of your work are you most excited about at the moment?

With this paper, we can now use a drop of blood to assess immune heath within minutes in a single-step user operation. We believe this work has great translational potential, and we are actively seeking new collaborators to test other diseases with immune dysfunctions.

In your opinion, what is the next step from creating your device to it being used for point-of-care testing in diabetes? and what are the most important questions to be asked/answered in this field of research?

Through this work and other recent work by our group, we have showed that diabetic leukocytes have distinct dielectric differences which can be used for immune health risk stratification. The next few important questions to ask is why are they different, and how we can further develop our technologies/assays to improve prognostic capabilities.

What do you find most challenging about your research?

As our work is highly interdisciplinary, the most challenging aspects are about finding the right people (collaborators, students etc.) and asking the right scientific questions (not too basic science, not too clinical and not too engineering)!

In which upcoming conferences or events may our readers meet you?

MicroTAS 2019 (Basel) and Microfluidics & Organ-on-a-Chip Asia Conference 2019 (Tokyo)

How do you spend your spare time?

Family time! Nowadays I enjoy spending time with my 18-month-old daughter Hannah, who never fails to amuse me or tire me out. If time permits, I will try to catch some US late-night talk shows too!

Which profession would you choose if you were not a scientist?

Tough choice! I’m torn between being a Lego/toy designer and a pilot.

Can you share one piece of career-related advice or wisdom with other early career scientists?

Talk to people outside your research disciplines. Learn to unlearn things if necessary because science and technology is advancing so fast.